# Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from text_processing.vi.graph_utils import (
    NEMO_NOT_QUOTE,
    GraphFst,
    delete_space,
)

try:
    import pynini
    from pynini.lib import pynutil

    PYNINI_AVAILABLE = True
except (ModuleNotFoundError, ImportError):
    PYNINI_AVAILABLE = False


class ElectronicFst(GraphFst):
    """
    Finite state transducer for verbalizing electronic
        e.g. tokens { electronic { username: "cdf1" domain: "abc.edu" } } -> cdf1@abc.edu
    """

    def __init__(self):
        super().__init__(name="electronic", kind="verbalize")
        user_name = (
            pynutil.delete("username:")
            + delete_space
            + pynutil.delete('"')
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete('"')
        )
        domain = (
            pynutil.delete("domain:")
            + delete_space
            + pynutil.delete('"')
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete('"')
        )

        protocol = (
            pynutil.delete("protocol:")
            + delete_space
            + pynutil.delete('"')
            + pynini.closure(NEMO_NOT_QUOTE, 1)
            + pynutil.delete('"')
        )

        graph = user_name + delete_space + pynutil.insert("@") + domain
        graph |= protocol

        delete_tokens = self.delete_tokens(graph)
        self.fst = delete_tokens.optimize()